Black carrots fermented with Aspergillus oryzae improves cognitive function and insulin resistance in β‐amyloid‐infused diabetic rats (829.4)

Abstract

We investigated whether the extracts of black carrot (BC) and BC fermented with Lactobacillus plantarum (BCLP) and Aspergillus oryzae (BCAO) can protect against cognitive dysfunction and glucose dysregulation in rats with Alzheimer’s disease and type 2 diabetes. Partial pancreatectomy and ICV β‐amyloid (25‐35) infusion into the CA1 region were fed either control diet (CON), 3% BC, BCAO, or BCLP in a high fat diet for 8 weeks. BCAO increased the contents of total anthocyanins compared to the BC. BC mainly contained cyanidin glycosides whereas after fermentation, the contents of peonidin derivatives increased in the ascending order of BCLP<BCAO. BCAO markedly decreased β‐amyloid deposition and improved hippocampal insulin signaling (pAkt◊pGSK◊pTau) in AD rats. Cognitive function was markedly impaired in AD rats and the cognitive dysfunction was prevented in an ascending order of CON<BC and BCLP<BCAO. BCAO blocked the decrease of whole body glucose infusion rates and the increase of hepatic glucose output at hyperinsulinemic state in AD rats. Interestingly, second phase insulin secretion during hyperglycemic clamp was rampantly increased in AD rats with remarkable decreased β‐cell mass. The BCAO treatment corrected the impaired insulin secretion and decreased β‐cell mass in AD rats. In conclusions, BCAO prevented their impairment of cognitive and glucose homoeostasis in AD diabetic rats as much as Non‐AD rats.